Hard against Baltimore-Washington International Airport, a neighborhood of tightly packed brick homes and basketball hoops is the subject of a debate inside the Federal Aviation Administration with national implications.

At issue is a new variety of jet noise first documented by airport engineers in September 1995. They found that, unlike most neighborhoods rimming major airports hit by high-frequency noise from jets passing overhead, homes along Allwood Drive were buffeted by low-frequency blasts from planes taking off.

The finding has significant implications: A $25 million soundproofing program run by the Maryland Aviation Authority with federal assistance is not effective in eliminating jet noise for the 82 homes in the area.

"This is a first," said Michael C. West, the MAA's associate administrator.

Sound engineers are studying the low-frequency thrum resulting from jet takeoffs, which occur every 4 1/2 minutes at BWI and shake the homes along Allwood Drive. They have set up jet simulators, huge concert-style speakers, in the neighborhood to blast two test homes with the chest-thumping noise to see how it differs from the common high-frequency pitch near airports.

"My home and another in the neighborhood are going to be like the guinea pigs," said Harry S. Cascio, who has lived with real jet blasts in the 200 block of Allwood Drive for 25 years.

"The whole house shakes. Windows shake. The noise is so bad you can't hear [anything] if you're talking to somebody."

Within months, the test results will reach the highest levels of the FAA, which has spent $570 million since 1982 helping homeowners across the country block jet noise from their living rooms. More money -- likely more than $100 million -- may be needed if the FAA decides to set health and safety standards for low-frequency noise. None exists now.

The FAA's decision, expected by summer, could have enormous implications -- not only for the 82 Allwood homeowners but for flight-path communities from Los Angeles to Boston.

A nondescript strip of split-level homes, Allwood is sitting at the crossroads of politics, public money and property rights.

For Allwood residents, some of whom have waited more than three years for government aid to soundproof their homes, the issue is a matter of peace and property values.

"This is a big opportunity for me," said Gordon H. Germuth Jr., whose house in the 200 block of Allwood Drive has been fitted with microphones and speakers for sound tests. "I just hope they aren't playing head games with us."

Del. Michael W. Burns, a Glen Burnie Republican who represents the neighborhood, said he is "very surprised that science has taken this long to catch up.

"I think the MAA is sincere about trying to deal with these noise issues. But I don't think they've put a high enough priority on it," he said.

More than 900 homes fall within BWI's 7,500-acre "noise zone," making them eligible for government help to block airport noise. Fifty-four Allwood homes appear eligible for some federal and state money; the owners of 24 have applied.

Since 1990, the MAA has received $10 million in federal grants and set aside about $2 million in state money to do the work. That is supposed to double by the time the program runs its course.

Almost 300 homes in such neighborhoods as Glen Burnie Park and Linthicum have either been soundproofed or sold under a program in which the MAA reimburses homeowners for lost property value. But no help has been given along Allwood Drive, and that may not change.

If the FAA decides against setting low-frequency noise standards, which MAA officials say is a possibility, Allwood residents might not be eligible for any assistance, leaving them with jet noise and dwindling property values.

High-frequency soundproofing, which involves replacing windows, doors and insulation, costs $25,000 per house. Two low-frequency soundproofing methods being tested along Allwood would cost $30,000 per house.

"I'm trying not to get anyone's expectations up," West said. "There are a number of possibilities. One is that we wouldn't be able to fund the improved soundproofing package."

Said Edward Johnson, who has lived in the 200 block of Allwood Drive for almost 20 years: "They're causing it. I think they should do something to stop it."

For the FAA, the debate involves a lot of money.

More than $100 million in claims could emerge from airport neighborhoods across the country if FAA administrators decide that low-frequency jet noise is a unique problem demanding special attention. Residents near Boston's Logan International Airport, for one, have a stake in the results.

Allwood Drive sits about 2,000 feet northwest of Runway 28R -- the main strip for an average of 325 jet takeoffs a day. The noise curls toward the homes in deep rumbles, which have reportedly cracked ceilings, caused sleepless nights and depressed property values.